//
// Created by Thinkpad on 2025/10/30.
//


#include <iostream>
using namespace std;

void say_age(const int& age) {
    // ++age; // Changing through const reference.Error
    cout << "hello,you are " << age << " years old." << endl;
}

int main(int argc,char **argv) {
    int age{23};
    cout << " age before :" << age << endl;
    say_age(age);
    cout << " age after :" << age << endl;
    return 0;
}